What Grid Sampling Tells Us about Nematode Population Dynamics.

In the spring of 2001, a geostatistical grid was established on a 2 ha field consisting of an unaligned regular design with12 m spacing with every other east-west row unaligned by 6 m.  Additional clustered samples were selected at 25 randomly chosen grid points, and an additional 25 samples were pulled for validation of predictive models.  This sampling pattern was repeated five more times during 2002-2005.  During this period, irrigation was established, and several cropping systems (wheat, barley, corn, and potato) and a biofumigant treatment were imposed.  This sampling allowed us to explore the temporal and spatial dynamics of the nematode populations relative to cropping system, biofumigants, and soil properties and fertility (texture, organic matter, soil inorganic N, pH, P, K, Ca, Mg, Zn, B).  In this paper we describe these relationships, and discuss using both spatial and non spatial statistical methods.